I had this issue also.
Made a ticket on PMDG Support and the answer was: "Francisco,
This issue is probably occurring because your FS entries are missing from the Windows registry. Please download Flight 1's Registry Repair Tool found here: http://www.flight1.com/view.asp?page=library Run it (IMPORTANT: make sure you right click and choose Run As Administrator if you're using Windows Vista or Windows 7) and select the option appropriate to the version of FS you're having issues with. Then, browse to that version of FS's folder and select the main exe file (either FS9.exe or FSX.exe) and press open.
This should resolve your issue, let us know if it doesn't." I did it, but the issue still remains. I'll try to disable the weather and turbulence.
